Solvent for Shellac

I've never mixed shellac from flakes before, and decided to get some and
try it.
All the literature I've seen advises using denatured alcohol to mix it
up with, and I made a mistake and bought Isopropyl alcohol.
Does anyone know if isoproply will act the same as denatured, or should
I go back to the store and get the right stuff?
TIA
Tanus

According to my copy of Understanding Wood Finishing by Bob Flexner, you can
use just about any kind of alcohol (methanol, ethanol, or isopropanol) to
dissolve shellac. As you may know, denatured alcohol is just ethanol that
has been made poisonous to avoid liquor taxes. Flexner states that the
advantages of denatured alcohol are that is cheap, less harmful to the
enviroment than other solvents, and it evaporates more slowly than methanol,
giving you more time to brush the shellac. Actually, isopropyl is even
better in this regard, as it evaporates even more slowly than ethanol.
Bottom line, you should be fine.
todd

This is not my area of expertise but I would not use drugstore
Isopropyl. (I use that stuff all the time to clean recording equipment
and such). Even the "lab grade" stuff has 9% water in it. AFAIK
"Denatured" alcohol contains no water, save that which has coalesced
into it from the atmosphere.

Sun, Sep 10, 2006, 10:20am (EDT-1) snipped-for-privacy@gmail.com (todd) doth
speaketh:
<snip> ethanol is very hygroscopic, I wonder how long it takes to get to
the same water content when exposed to the air.
No prob. Use Everclear. When the project is done, safely and
sanely dispose of the leftover. Get a new supply next project. No
prob.
JOAT
I am not paranoid. I do not "think" people are after me. I "know" damn
well they're after me.

Shellac is most commonly dissolved in denatured alcohol which is ethanol
with some denaturant that is poisonous but still appropriate to the
application. For shellac we prefer, as denaturants, a small amount of
methanol (less than 5%, I believe, I don't have that spec handy) and
another small dose of isopropyl added to keep you from drinking it (and
thus avoiding paying all those sin taxes to the Feds.) But shellac will
dissolve in other alcohols and even acetone and those will effect the
drying time of the solution. Acetone dries way fast and isopropyl dries
much more slowly and is often added as a drying retardant for spraying.
If you use isopropyl, get the highest percentage you can find as most
rubbing-alcohol types have too much water in them.
Hardware store denatured alcohol works well with shellac but contains 5%
or more water. Water and alcohol love each other and are hard to
separate. In fact, if you mix equal parts water and alcohol, you'll get
about 4% less than double the amount of mixture because they combine so
intimately. The water in denatured alcohol can inhibit the dissolving of
the flakes and slow the dry-time of the finish. Therefore, we offer
anhydrous denatured alcohol which has had most of its water removed
(it's very costly to get it all) for the demanding finisher. Also,
alcohol loves water so much it will absorb it from the air any chance
you give it so keep your containers of alcohol and your freshly mixed
shellac tightly sealed.
Tanus wrote:

Sun, Sep 10, 2006, 8:13pm (EDT+4) snipped-for-privacy@earthlink.net (CW) doth
wistfully query:
I'll take your word for most of this but 1+1=1.96?
New math. Guaranteed 96% accurate.
JOAT
I am not paranoid. I do not "think" people are after me. I "know" damn
well they're after me.

Volume.
It's a little harder to change the mass. I guess my OP should have said
"equal volumes" instead of equal "parts". "Parts" being too ambiguous
for this forum.
This from wikipedia:
"Several unusual phenomena are associated with mixtures of ethanol and
water. Ethanol-water mixtures have less volume than their individual
components: a mixture of equal volumes ethanol and water has only 96% of
the volume of equal parts ethanol and water, unmixed. The addition of
even a few percent of ethanol to water sharply reduces the surface
tension of water. This property partially explains the tears of wine
phenomenon: when wine is swirled inside a glass, ethanol evaporates
quickly from the thin film of wine on the wall of the glass. As its
ethanol content decreases, its surface tension increases, and the thin
film beads up and runs down the glass in channels rather than as a
smooth sheet."
CW wrote:

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